/Engine/Source/Editor/MainFrame/Public/Interfaces/IMainFrameModule.h
Register a new callback for determining if the editor can be closed
[FDelegateHandle](API\Runtime\Core\Delegates\FDelegateHandle) RegisterCanCloseEditor ( const [FMainFrameCanCloseEditor](API\Editor\MainFrame\Interfaces\IMainFrameModule\FMainFrameCanCloseEditor) & InDelegate )